In this source code example, we will demonstrate the usage of String.CompareTo() method in C# with an example.

The C# CompareTo() method is used to compare a String instance with a specified String object. It indicates whether this String instance precedes, follows, or appears in the same position in the sort order as the specified string or not.

C# String CompareTo Method Example

The following example uses the CompareTo method to compare the current string instance with another string.

using System;

public class StringDemo
{
    public static void Main(string[] args)
    {
        string strFirst = "Goodbye";
        string strSecond = "Hello";
        string strThird = "a small string";
        string strFourth = "goodbye";
        
        // Compare a string to itself.
        Console.WriteLine(CompareStrings(strFirst, strFirst));
        
        Console.WriteLine(CompareStrings(strFirst, strSecond));
        Console.WriteLine(CompareStrings(strFirst, strThird));
        
        // Compare a string to another string that varies only by case.
        Console.WriteLine(CompareStrings(strFirst, strFourth));
        Console.WriteLine(CompareStrings(strFourth, strFirst));     

    }
    
    private static string CompareStrings( string str1, string str2 )
   {
      // Compare the values, using the CompareTo method on the first string.
      int cmpVal = str1.CompareTo(str2);

       if (cmpVal == 0) // The strings are the same.
         return "The strings occur in the same position in the sort order.";
      else if (cmpVal < 0)
         return "The first string precedes the second in the sort order.";
      else
         return "The first string follows the second in the sort order.";
    }
}

Output:

The strings occur in the same position in the sort order.
The first string precedes the second in the sort order.
The first string follows the second in the sort order.
The first string follows the second in the sort order.
The first string precedes the second in the sort order.

Related C# String Examples

1. C# String Clone Method Example
2. C# String Compare Method Example
3. C# String CompareTo Method Example
4. C# String Concat Method Example
5. C# String Contains Method Example
6. C# String Copy Method Example
7. C# String CopyTo Method Example
8. C# String EndsWith Method Example
9. C# String Equals Method Example
10. C# String GetEnumerator Method Example
11. C# String GetHashCode Method Example
12. C# String IndexOf Method Example
13. C# String Insert Method Example
14. C# String Intern Method Example
15. C# String IsNullOrEmpty Method Example
16. C# String IsNullOrWhiteSpace Method Example
17. C# String LastIndexOf Method Example

References

https://docs.microsoft.com/en-us/dotnet/api/system.string.compareto?view=net-6.0